Square.



' and formed with a centrally arranged notch I UNITED STATES PATENT OFFICE.

NICHOLAS B. MCGRA'IH, OF SOUTHINGTON, CONNECTICUT.

SQUARE.

' Application filed April 25,

To all whom it may concern:

lie it known that l, Xicnoms 15. )[c- (tuvru. a citizen of the United States,residing at Southington. in the county of Hartford amt State of Connecticut. have in, vented a new and useful Improvement in Squares; and I do hereby declare the 'l'ollowing. when taken in connection with the act compairving drawings and the numerals ot reference marked thereon, to be a full, clear, and exact description of the same, and which said drawings constitute part of this specification. and represent, in--.

Figure l a plan view of a square eonstructed in accordance with my invention. Fig. 2 an enlarged plan view of the inner end of the finger of the. tongue.

Fig. 3 an underside view of the locking block.

Fig.4; a sectional view on the line 4% of Fi 1. Fig. 5 a sectional view on the line 5-0 of Fig. 1.

lhis invention relates to an improvement in squares, and particularly to squares of the so called take-down type; that is, a square in which the tongue is separable from the body.

The object ot this invention is to provide simple and convenient means whereby the tongue may be firmly interlocked with the body; and the invention consists in the construction hereii'ia't'ter described and particularly. recited in the claims.

In carrying out my invention the body 2 is formed with a head 3 slightly projecting beyond the body, and extending across the face of the head and upper end of the body is an undercut recess or groove 4:, and mounted at the inner end of the recess is a rotating locking-block 5 formed in its ander face with a spiral rib ti havinga st0p-. surface 9 and a cam 10 for the purpose as will hereinafter appear. The tongue 11 -is formed with a linger 12 having beveled edges adapted to closely fit in the groove t. This finger is arranged at its inner end 13 to clear the locking-block 5 and the face of the finger is cutaway to extend beneath the surface of the block, and in this cut away portion is a segmental rib l t. The finger 12 is inserted into the groove 4, the block 5 being turned so that the rib (5 will not obstruct its movement. When in substantially the limit of its inward movement the block 5 is turnedcausing the rib 6 to Specification of Letters Patent.

Patented Jtii 19,1910.

1910. Serial No. 557,358

' with a transverse slot 16 as shown in broken lines Fig. 5, for the introduction of a screw driver or other convenient. tool by which the block may be turned. 'lhetongue is therefore drawn into position and locked by the block. The tit of the finger 12 in the groove -t must be a very close one, and consequently the tongue cannot be readily removed even when the block is turned, and to facilitate its removal the cam 10 will when the block is moved into its unlocking position, engage with one end of the rib it and force the linger 1'2 slightly outward so that the tongue may be more conveniently withdrawn.

1. In a square, the combination with a body formed at. its upper end with an undercut groove, a. rotatable locking block n'iounted at the inner end of said groove and formed in its inner face with a rib, combined with a tongue having a beveled finger adapted to be entered into said groove, notched at its inner end to eleainsaid locking-block, and formed with a. segmental rib "with which the rib of the locking block may engage, whereby when the block is turned the tongue will be locked to the body.

2. In a. square, the combination with a body formed at its upper end with an undercut groove, a rotatable locking block mounted at the inner end of said groove and formed in itsinner face wit-h a segmental rib having a spiral surface, and with a cam, combined with a tongue having a beveled finger adapted to be entered into said groove, notched at its inner end to clear said locking block and formed with a segmental rib with which the rib of the locking block may engage and with the end of which the said cam may engage, whereby whenthe block is turned the tongue will be locked to the body or forced outward therefrom.

In testimony whereof, I have signed this specification in the presence of two sub- \Vitnesses:

JOHN, P. MCGRATII,

EDWARD H. WnLon. 

